1. Field of the Invention
The present invention relates to buckle and more particularly, to a safety buckle, which is automatically unlocked when stretched by a force over a predetermined level.
2. Description of the Related Art
For fastening purpose, woven belts are intensively used in different products including collar and harness for pet, baby cradle, backpack, safety helmet, slipper, safety jacket, cargo and passenger safety belts, etc. For a wide range of application to different products, a belt must be used with a buckle.
For example, a collar for cat is usually used with a safety buckle so that the collar can automatically be unfastened if the collar is detained by an object during jumping of the cat, preventing a hurt to the cat. In other words, the safety buckle is automatically unlocked to unfasten the collar from the cat for letting the cat go freely without hurt when the collar received a stretching force over the limited range (normally about 10 lbs or 5 kgs). A collar for cat is normally used for holding a nameplate, bell, or any of a variety of ornamental devices.
FIG. 1 shows a prior art design safety buckle. Similar to conventional side release buckles, the safety buckle 50 is comprised of a male buckle member 51 and a female buckle member 52. The male buckle member 51 comprises an insertion slot 53 transversely provided at the rear side for the mounting of a belt, a center shaft 55 forwardly extended from the front side thereof on the middle, and two locking bars 54a and 54b forwardly extended from the front side and equally spaced from the center shaft 55 at two sides. The locking bars 54a and 54b each have a front end terminating at a hooked portion 59a or 59b. The female buckle member 52 comprises a receiving open chamber 57 adapted to receive the center shaft 55 and locking bars 54a and 54b of the male buckle member 51, and two side retaining holes 58a and 58b symmetrically disposed at two opposite lateral sides for receiving the hooked portions 59a and 59b of the locking bars 54a and 54b. As illustrated in FIG. 2, when squeezing the two locking bars 54a and 54b inwards toward the inside of the female buckle member 52, the hooked portions 59a and 59b of the locking bars 54a and 54b are respectively disengaged from the retaining holes 58a and 58b of the female buckle member 52, and therefore the male buckle member 51 is released from the female buckle member 52. To be different from conventional side release buckles, the hooked portions 59a and 59b of the locking bars 54a and 54b of the female buckle member 51 of the safety buckle 50 have a smoothly arched outer surface so that the male buckle member 51 can quickly be disconnected from the female buckle member 52 when the belt (collar) connecting between the male buckle member 51 and the female buckle member 52 is stretched by a force surpassed a predetermined range. Conventional side release buckles are designed to bear a relatively higher stretching force.
Because the aforesaid safety buckle is similar to conventional side release buckles in shape and structure, it does not attract consumers to use.